Exceptional Memory Explained: How Some People Remember What They Had for Lunch 20 Years Ago

Researchers from the University of California, Irvine reported in 2006 on a woman named Jill Price who could remember in great detail what she did on a particular day decades earlier. James McGaugh, Larry Cahill and Elizabeth Parker put the woman through a battery of tests and ascertained that she was not using any of the memory tricks that have been known to mnemonists for millennia.

Word got out, the media descended and the lab now receives calls every day from people who say they have the same ability as Price. Of the hundreds of people interviewed, 22 appear to exhibit what the researchers call highly superior autobiographical memory (HSAM), the detailed recollection of events that occurred in the distant past.

A question that has persisted about this line of research is whether the brains of these people are distinct from the organs of others who can’t remember yesterday’s lunch, let alone trivial events from 20 years back. Preliminary research presented at SFN 2011 by the Irvine investigators suggests that there may be real differences in the brain structures of these people. MRI studies of 11 study participants demonstrate that multiple areas in the temporal and the parietal lobes tied to autobiographical memory are significantly larger than the same regions in a control group. At the same time, another area, the lentiform nucleus, linked to obsessive-compulsive disorder, is also bigger. Some of the study participants, in fact, have a tendency to hoard things or avoid germs, though none have been diagnosed with OCD.

“There seems to be this extreme organizational capacity, kind of like the tricks that mnemonists use,” says Howard Eichenbaum, a Boston University professor who is editor of the journal Hippocampus. “But the brain is doing it subversively under the radar so to speak. This process must interact with the hippocampus, which is taking these autobiographical memories and helping to sort things out the way that mnemonists sort out a long list of words.”

Superior autobiographical memory is not a “genius” trait and those in the study do not exhibit better cognition in other realms nor do they count Nobelists among their ranks—one is an actress (Marilu Henner) another is a radio reporter, to name just two. They are not even natural card counters. They perform no better than a control group on tests of short-term memory skills—rote memorization of a string of numbers, for instance.

The advantages of a capacious autobiographical memory are not as obvious as they might seem. Most of the HSAM group relishes its special ability, but many wrestle with how they can use it in their daily lives. “The number one question from people who call us is what can I do with my memory,” says Aurora Leport, a graduate student from Cahill’s lab who is presenting the research at SFN on Tuesday. The callers want to know how they can use the skill “in a positive way” or simply how they can use it to make money. “I don’t really know how to answer that, Leport says. “It’s shocking to me that they can’t use it better.” It isn’t really a superpower. It’s not a key that allows them to do amazing things.”

Extraordinary memory can become an overwhelming burden, the ultimate in information overload, as witnessed by the case of Solomon Shereshevsky, profiled by the renowned psychologist Alexander Luria (1902-1977) in The Mind of a Mnemonist. A photographic memory like Shereshevsky’s captures and retains the most minute details of a text or image. Like memorizing the phone book. HSAM, by contrast, allows the recollection of your life as a fifteen-year old as if it were only yesterday, but not at high resolution: You may remember that you ate cereal for breakfast on Feb. 15, 1989, but not every ingredient on the box.

Although they are emotionally well adjusted, some of the superior memory group has to continually come to terms with the vividness with which they recall negative memories from 10, 20, 30 years before. “When I ask them about a bad memory, they say it comes back to them with the same amount of detail,” Leport says, but it also comes back to them with the amount of emotion at the time of the event so they have to deal with that.”

The discovery of HSAM could provide a new direction for researchers. The famous patient Henry Molaison, better known as HM, was unable to form new long-term memories because of surgical damage to the medial temporal lobe, which includes the hippocampus. But study of his case greatly deepened the understanding of how memory works. Superior autobiographical memory could, in theory, give neuroscientists insights from the opposite pole. “We have a new tool in which we can look at memory when it’s functioning at a higher level,” LePort says. These studies might also furnish a new appreciation of the critical balancing act between remembering and forgetting to keep from getting overpowered by thought and emotion.

Source: University of California, Irvine

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Gary Stix

Gary Stix is a senior editor at Scientific American. He writes the blog Talking Back at ScientificAmerican.com.

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